Joe Biden has dismissed the sabre-rattling threats made by Vladimir Putin as the US president met the UK prime minister, Keir Starmer, at the White House.

Biden said on Friday afternoon he did not accept that Ukraine using western-made Storm Shadow missiles to bomb targets in Russia would amount to Nato going to war with Moscow.

At a foreign policy summit, Biden said: “I do not think much about Vladimir Putin.”

Biden and Starmer’s top foreign policy teams were meeting at the Blue Room in the White House. At the start of the meeting, James Matthews from Sky News jumped the gun by asking Biden: “What do you say to Vladimir Putin’s threat of war?”

Biden scolded him. “You be quiet, I’m going to speak, OK?” the president said, before beginning his prepared remarks.

Also present at the Blue Room meeting were Antony Blinken, the US secretary of state, and David Lammy, the UK foreign secretary. Other British participants included Tim Barrow, the national security adviser, and Starmer’s chief of staff, Sue Gray.

Starmer flew over from London on Thursday for the working meeting amid escalating tensions with the Kremlin after the UK had indicated that the US had agreed to allow Ukraine to use Storm Shadow missiles to bomb Russia.

After the summit, Starmer said the meeting was not about a particular decision on Storm Shadow. “Well, we’ve had a long and productive discussion on a number of problems, including Ukraine, as you’d expect, the Middle East, and the Indo-Pacific, talking strategically about tactical decisions,” he said.

However, Biden indicated the topic came under discussion between the leaders and their teams. In response to a shouted question asking how soon he was prepared to let Ukraine fire missiles deeper into Russia, Biden said: “We’re going to discuss that now.”

Neither of the presidential candidates, Kamala Harris and Donald Trump, were in the capital and available to meet Starmer because both were campaigning.

Starmer said he had never spoken to Harris. The prime minister did speak to Trump briefly after the former president survived an assassination attempt in the summer.

The British Storm Shadow missiles, made by a European company, can strike targets at least 190 miles away and Ukraine wants to use them to bomb airbases, missile sites and other military targets in the Russian heartlands.

Earlier, Russia announced it had revoked the accreditation of six British diplomats in Moscow on accusations of espionage. Moscow’s FSB domestic spy agency said on Friday that it had acted on documents showing part of the Foreign Office was helping coordinate what it called “the escalation of the political and military situation” in Ukraine.

The Foreign Office, however, said the move had been made last month as part of a continuing diplomatic tit-for-tat. Sources indicated the British diplomats had left Russia weeks ago and were being replaced.

A Foreign Office spokesperson said: “The accusations made today by the FSB against our staff are completely baseless … We are unapologetic about protecting our national interests.”

The British government expelled the Russian defence attache in May, accusing him of being an undeclared intelligence officer, and removed diplomatic status from several Russian-owned buildings in the UK.

The Biden-Starmer meeting was called at the request of the UK, the White House said. After a short one-to-one between the leaders, no press conference was scheduled.

The UK government has for days been dampening down expectations of a public announcement about Storm Shadow being used in Ukraine – though the discussions prompted Putin to warn on Thursday that allowing Ukraine to use western-made long-range missiles would amount to Nato being at war with Russia.

Starmer, however, told reporters as he flew into Washington: “Russia started this conflict. Russia illegally invaded Ukraine. Russia can end this conflict straight away. Ukraine has the right to self-defence.” Putin had been expected to counter talk of fresh help for Kyiv with threats.

Ukraine’s president, Volodymyr Zelenskiy, has been pushing for months for permission to use the missiles, including during talks this week with Lammy and Blinken.

British sources say London and Washington have decided to allow Ukraine to use long-range missiles, but are not yet willing to announce it. Deploying the missiles, western officials add, should be part of a wider plan designed to try to bring about an end to the full-scale war.

Zelenskiy pleaded on Friday for the US and UK to speed up the process and allow Kyiv to make the war “more difficult for Russia”.

In a lengthy statement, Zelenskiy said: “Anyone who sees a map where Russia launches its strikes from, trains its forces, keeps its reserves, locates its military facilities, and what logistics [it] uses clearly understands why Ukraine needs long-range capabilities.”

Ukrainian leaders are intensely frustrated that the Kremlin is able to launch deadly missile strikes across Ukraine, while they are unable to target sites in Russia because the weapons available are manufactured in the west and until now western governments have not approved such use.

Storm Shadow is made by a company controlled by British, French and Italian interests, and some of its components are made in the US, giving all four countries a veto on its use. Ukraine has only a limited long-range missile capability of its own making.

The Russian embassy in London said Britain was wasting money in supporting Ukraine, that any arms donated would “likely go up in smoke” and that the policy of helping Kyiv would “provide no relief to ordinary Brits, who are preparing to tighten their belts as winter approaches”.